Klinefelter Syndrome Important
It is possible that the main title of the report Klinefelter Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.

Synonyms

• KS
• XXY male
• XX male
• XXYY male
• XXXY male
• XXXXY male

Disorder Subdivisions

• None

General Discussion

Klinefelter syndrome is a group of chromosomal disorders in males in which one or more extra X chromosomes are present. Males with the classic form of the disorder have one extra X chromosome. Males with variant forms of Klinefelter syndrome have additional X and/or Y chromosomes. The extra X and/or Y chromosome can affect physical, developmental, behavioral, and cognitive functioning. Common physical features may include tall stature, lack of secondary pubertal development, small testes (hypogonadism), delayed pubertal development, and breast development (gynecomastia) in late puberty. These features may be associated with low testosterone level and elevated gonadotropin levels.

Resources

March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
Tel: (914)997-4488
Fax: (914)997-4763
Tel: (888)663-4637
Email: Askus@marchofdimes.com
Internet: http://www.marchofdimes.com

49 XXXXY
870 Miranda Green
Palo Alto, CA 94306
USA
Tel: (360)892-7547
Email: epwatzka@gmail.com
Internet: http://www.xxxxysyndrome.com/index.htm

Klinefelter Syndrome Association of Canada
42 Ritson Road South, Upper floor,
Oshawa
Ontario, L1H 5G9
Canada
Tel: 9059262942
Email: dj.rabinovitch@gmail.com

NIH/National Institute of Child Health and Human Development
31 Center Dr
Building 31, Room 2A32
MSC2425
Bethesda, MD 20892
Fax: (866)760-5947
Tel: (800)370-2943
TDD: (888)320-6942
Email: NICHDInformationResourceCenter@mail.nih.gov
Internet: http://www.nichd.nih.gov/

American Association for Klinefelter Syndrome Information and Support
c/o Roberta Rappaport
3796 Ogden Ln.
Mundelein, IL 60060-6038
USA
Tel: (888)466-5747
Email: KSinfo@aaksis.org
Internet: http://www.aaksis.org

Klinefelters Syndrome Support Group of Australia
Kellyville
New South Wales, 2155
Australia
Tel: 04 25240773
Email: YATESBECKS@bigpond.com

XXYY Project
PO Box 2172
Littleton, CO 80161-2172
USA
Tel: (215)394-5942
Email: inquiry@xxyysyndrome.org
Internet: http://xxyysyndrome.org

Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
TDD: (888)205-3223
Internet: http://rarediseases.info.nih.gov/GARD/

Madisons Foundation
PO Box 241956
Los Angeles, CA 90024
Tel: (310)264-0826
Fax: (310)264-4766
Email: getinfo@madisonsfoundation.org
Internet: http://www.madisonsfoundation.org

Klinefelter Syndrome & Associates
P.O. Box 872
Pine, CO 80470-0872
Tel: (303)400-9040
Fax: (303)838-0753
Tel: (888)999-9428
Email: info@genetic.org
Internet: http://www.genetic.org

Focus Foundation, Inc.
PO Box 190
Davidsonville, MD 21035
Tel: (443)223-7323
Fax: (410)798-4801
Email: info@thefocusfoundation.org
Internet: http://www.thefocusfoundation.org